1. Field of the Invention
This invention relates to a chemical surface treatment system for workpieces, in particular a system for sequentially subjecting workpieces to a series of associated liquid chemical baths for treating a surface or surfaces of the workpiece.
2. Discussion of Related Art
It is known in the prior art to provide a workpiece surface chemical treatment system comprising a row or line of associated workstations for successively treating a workpiece that is moved from station to station to chemically treat the entire workpiece or selected surfaces thereof. For example, a high speed electroplating system is known wherein workpieces are automatically transferred from one station to the next for the purpose of degreasing the workpiece, subjecting the workpiece to alkali and acid baths, anodizing the workpiece and ultimately electroplating the workpiece in a conventional manner. It is also known that such workstations can be arranged to treat interior surfaces of a chamber or a hollow portion of a workpiece at a high rate of speed.
To accommodate the automated work transfer system, and to simplify the advancement of the workpiece along the row of workstations, for example in a high speed chemical plating system, it is highly desirable to space the workstations at substantially equal increments of distance to the extent possible, for obvious reasons. On the other hand, it is not always practical or possible to space the workstations at equal increments, particularly in those situations where one or more of the workstations includes auxiliary equipment that requires it to be greater in length than other or adjacent workstations in the system. This is particularly the case in a situation where the workpiece comprises an object having a hollow chamber with ports that must be plugged during chemical treatment of the interior surfaces of the chamber with a circulating liquid solution. An example of such a workpiece would be an engine cylinder having sparkplug, intake and exhaust ports that must be plugged during chemical treatment of the cylinder bore. Typically, in a high speed plating system, the system for plugging the ports in the workpiece entails the use of automatically actuated plugs for the ports and auxiliary actuating fluid motors or cylinders for the plugs that require additional workstation length to accommodate the motor cylinders or other equipment required at the workstation.
The problem, therefore, is to provide a system of the type mentioned wherein workpieces can be automatically sequentially moved equal increments of length along the row of workpiece treating workstations while accommodating individual workstations that have a greater length than the remaining workstations along the main row or line. Obvious benefits would flow from the ability to move the workpieces at equal increments from station to station, including simplification of the work transfer control system and avoidance of increasing the total length of the workpiece processing line.
An incidental problem associated with chemical treatment of workpieces using liquid chemical solutions that are corrosive or otherwise detrimental to the integrity of the workstation hardware is the fact that leakage or drippage of chemical treating solution along the row of workstations as the workpieces are transferred from station to station causes corrosion of the workstation equipment. It is desirable to remove residual liquid chemical solution from the workpieces immediately after treatment before they are advanced along the treatment line.